	package com.bbn.mt.terp;
// package bbn.mt.ster;
// NOTE: This is a GROTESQUE Java implementation of Porter stemming, obviously written
// by a life-long C programmer who doesn't understand Java String class or Java at all.
// But, it gets the job done!
/*

 Porter stemmer in Java. The original paper is in

 Porter, 1980, An algorithm for suffix stripping, Program, Vol. 14,
 no. 3, pp 130-137,

 See also http://www.tartarus.org/~martin/PorterStemmer

 History:

 Release 1

 Bug 1 (reported by Gonzalo Parra 16/10/99) fixed as marked below.
 The words 'aed', 'eed', 'oed' leave k at 'a' for step 3, and b[k-1]
 is then out outside the bounds of b.

 Release 2

 Similarly,

 Bug 2 (reported by Steve Dyrdahl 22/2/00) fixed as marked below.
 'ion' by itself leaves j = -1 in the test for 'ion' in step 5, and
 b[j] is then outside the bounds of b.

 Release 3

 Considerably revised 4/9/00 in the light of many helpful suggestions
 from Brian Goetz of Quiotix Corporation (brian@quiotix.com).

 Release 4

 */
import java.io.FileInputStream;
import java.io.FileNotFoundException;
import java.io.IOException;
import java.io.Serializable;
import java.util.ArrayList;
import java.util.HashMap;
import java.util.HashSet;
import java.util.Map;
import java.util.Set;
/**
 * Stemmer, implementing the Porter Stemming Algorithm
 * 
 * The Stemmer class transforms a word into its root form. The input word can be
 * provided a character at time (by calling add()), or at once by calling one of
 * the various stem(something) methods.
 */
class Porter implements Serializable
{
	/**
	 * 
	 */
	private static final long serialVersionUID = -72097756069341400L;
	private char[] b;
	private int i, /* offset into b */
	i_end, /* offset to end of stemmed word */
	j, k;
	private final int INC = 50;
	/* unit of size whereby b is increased */
	// A static singleton instance to support calling the instance methods.
	// It might be better to make this whole thing a static class
	//private static Porter instance = new Porter();
	//private static Porter instance = null;
	private final Cache equivCache = new Cache();
	private final Map stemCache = new HashMap();
	private TERpara params = null;
	
	/*public static Porter getInstance(TERpara params)
	{
		if(instance == null)
			instance = new Porter(params);
		return instance;
	}*/
	
	public boolean equivStems(Comparable word1, Comparable word2)
	{
		return equivStems(word1.toString(), word2.toString());
	}
	public boolean equivStems(Comparable word1, ArrayList<Comparable<String>> w2)
	{
		for(Comparable<String> word2 : w2)
		{	
			if(equivStems(word1.toString(), word2.toString()))
				return true;
		}
		return false;
	}
	public boolean equivStems(String word1, String word2)
	{
		if (equivCache.hasValue(word1, word2))
			return equivCache.isTrue(word1, word2);
		else
		{
			boolean value = stem(word1).equals(stem(word2));
			equivCache.setValue(word1, word2, value);
			return value;
		}
	}
	public void clearCache()
	{
		stemCache.clear();
		equivCache.clear();
	}
	public Set getEquivalents(String word)
	{
		if (params.para().get_boolean(TERpara.OPTIONS.USE_PORTER))
			return equivCache.getEquivalents(word);
		else
		{
			Set set = new HashSet();
			set.add(word);
			return set;
		}
	}
	public String stem(String word)
	{
		if (!(params.para().get_boolean(TERpara.OPTIONS.USE_PORTER)))
			return word;
		String stem = (String) stemCache.get(word);
		if (stem == null)
		{
			//stem = instance.stem0(word).intern();
			stem = stem0(word).intern();
			stemCache.put(word, stem);
		}
		return stem;
	}
	private String stem0(String word)
	{
		// System.out.println("STEMMING");
		add(word.toCharArray(), word.length());
		stem();
		return toString();
	}
	private Porter()
	{
		b = new char[INC];
		i = 0;
		i_end = 0;
	}
	
	public Porter(TERpara params)
	{
		this();
		this.params = params;
	}
	
	/**
	 * Add a character to the word being stemmed. When you are finished adding
	 * characters, you can call stem(void) to stem the word.
	 */
	private void add(char ch)
	{
		if (i == b.length)
		{
			char[] new_b = new char[i + INC];
			for (int c = 0; c < i; c++)
				new_b[c] = b[c];
			b = new_b;
		}
		b[i++] = ch;
	}
	/**
	 * Adds wLen characters to the word being stemmed contained in a portion of
	 * a char[] array. This is like repeated calls of add(char ch), but faster.
	 */
	private void add(char[] w, int wLen)
	{
		if (i + wLen >= b.length)
		{
			char[] new_b = new char[i + wLen + INC];
			for (int c = 0; c < i; c++)
				new_b[c] = b[c];
			b = new_b;
		}
		for (int c = 0; c < wLen; c++)
			b[i++] = w[c];
	}
	/**
	 * After a word has been stemmed, it can be retrieved by toString(), or a
	 * reference to the internal buffer can be retrieved by getResultBuffer and
	 * getResultLength (which is generally more efficient.)
	 */
	public String toString()
	{
		return new String(b, 0, i_end);
	}
	/**
	 * Returns the length of the word resulting from the stemming process.
	 */
	private int getResultLength()
	{
		return i_end;
	}
	/**
	 * Returns a reference to a character buffer containing the results of the
	 * stemming process. You also need to consult getResultLength() to determine
	 * the length of the result.
	 */
	private char[] getResultBuffer()
	{
		return b;
	}
	/* cons(i) is true <=> b[i] is a consonant. */
	private final boolean cons(int i)
	{
		switch (b[i])
		{
			case 'a' :
			case 'e' :
			case 'i' :
			case 'o' :
			case 'u' :
				return false;
			case 'y' :
				return (i == 0) ? true : !cons(i - 1);
			default :
				return true;
		}
	}
	/*
	 * m() measures the number of consonant sequences between 0 and j. if c is a
	 * consonant sequence and v a vowel sequence, and <..> indicates arbitrary
	 * presence,
	 * 
	 * <c><v> gives 0 <c>vc<v> gives 1 <c>vcvc<v> gives 2 <c>vcvcvc<v> gives 3
	 * ....
	 */
	private final int m()
	{
		int n = 0;
		int i = 0;
		while (true)
		{
			if (i > j)
				return n;
			if (!cons(i))
				break;
			i++;
		}
		i++;
		while (true)
		{
			while (true)
			{
				if (i > j)
					return n;
				if (cons(i))
					break;
				i++;
			}
			i++;
			n++;
			while (true)
			{
				if (i > j)
					return n;
				if (!cons(i))
					break;
				i++;
			}
			i++;
		}
	}
	/* vowelinstem() is true <=> 0,...j contains a vowel */
	private final boolean vowelinstem()
	{
		int i;
		for (i = 0; i <= j; i++)
			if (!cons(i))
				return true;
		return false;
	}
	/* doublec(j) is true <=> j,(j-1) contain a double consonant. */
	private final boolean doublec(int j)
	{
		if (j < 1)
			return false;
		if (b[j] != b[j - 1])
			return false;
		return cons(j);
	}
	/*
	 * cvc(i) is true <=> i-2,i-1,i has the form consonant - vowel - consonant
	 * and also if the second c is not w,x or y. this is used when trying to
	 * restore an e at the end of a short word. e.g.
	 * 
	 * cav(e), lov(e), hop(e), crim(e), but snow, box, tray.
	 */
	private final boolean cvc(int i)
	{
		if (i < 2 || !cons(i) || cons(i - 1) || !cons(i - 2))
			return false;
		{
			int ch = b[i];
			if (ch == 'w' || ch == 'x' || ch == 'y')
				return false;
		}
		return true;
	}
	private final boolean ends(String s)
	{
		int l = s.length();
		int o = k - l + 1;
		if (o < 0)
			return false;
		for (int i = 0; i < l; i++)
			if (b[o + i] != s.charAt(i))
				return false;
		j = k - l;
		return true;
	}
	/*
	 * setto(s) sets (j+1),...k to the characters in the string s, readjusting
	 * k.
	 */
	private final void setto(String s)
	{
		int l = s.length();
		int o = j + 1;
		for (int i = 0; i < l; i++)
			b[o + i] = s.charAt(i);
		k = j + l;
	}
	/* r(s) is used further down. */
	private final void r(String s)
	{
		if (m() > 0)
			setto(s);
	}
	/*
	 * step1() gets rid of plurals and -ed or -ing. e.g.
	 * 
	 * caresses -> caress ponies -> poni ties -> ti caress -> caress cats -> cat
	 * 
	 * feed -> feed agreed -> agree disabled -> disable
	 * 
	 * matting -> mat mating -> mate meeting -> meet milling -> mill messing ->
	 * mess
	 * 
	 * meetings -> meet
	 */
	private final void step1()
	{
		if (b[k] == 's')
		{
			if (ends("sses"))
				k -= 2;
			else if (ends("ies"))
				setto("i");
			else if (b[k - 1] != 's')
				k--;
		}
		if (ends("eed"))
		{
			if (m() > 0)
				k--;
		}
		else if ((ends("ed") || ends("ing")) && vowelinstem())
		{
			k = j;
			if (ends("at"))
				setto("ate");
			else if (ends("bl"))
				setto("ble");
			else if (ends("iz"))
				setto("ize");
			else if (doublec(k))
			{
				k--;
				{
					int ch = b[k];
					if (ch == 'l' || ch == 's' || ch == 'z')
						k++;
				}
			}
			else if (m() == 1 && cvc(k))
				setto("e");
		}
	}
	/* step2() turns terminal y to i when there is another vowel in the stem. */
	private final void step2()
	{
		if (ends("y") && vowelinstem())
			b[k] = 'i';
	}
	/*
	 * step3() maps double suffices to single ones. so -ization ( = -ize plus
	 * -ation) maps to -ize etc. note that the string before the suffix must
	 * give m() > 0.
	 */
	private final void step3()
	{
		if (k == 0)
			return; /* For Bug 1 */
		switch (b[k - 1])
		{
			case 'a' :
				if (ends("ational"))
				{
					r("ate");
					break;
				}
				if (ends("tional"))
				{
					r("tion");
					break;
				}
				break;
			case 'c' :
				if (ends("enci"))
				{
					r("ence");
					break;
				}
				if (ends("anci"))
				{
					r("ance");
					break;
				}
				break;
			case 'e' :
				if (ends("izer"))
				{
					r("ize");
					break;
				}
				break;
			case 'l' :
				if (ends("bli"))
				{
					r("ble");
					break;
				}
				if (ends("alli"))
				{
					r("al");
					break;
				}
				if (ends("entli"))
				{
					r("ent");
					break;
				}
				if (ends("eli"))
				{
					r("e");
					break;
				}
				if (ends("ousli"))
				{
					r("ous");
					break;
				}
				break;
			case 'o' :
				if (ends("ization"))
				{
					r("ize");
					break;
				}
				if (ends("ation"))
				{
					r("ate");
					break;
				}
				if (ends("ator"))
				{
					r("ate");
					break;
				}
				break;
			case 's' :
				if (ends("alism"))
				{
					r("al");
					break;
				}
				if (ends("iveness"))
				{
					r("ive");
					break;
				}
				if (ends("fulness"))
				{
					r("ful");
					break;
				}
				if (ends("ousness"))
				{
					r("ous");
					break;
				}
				break;
			case 't' :
				if (ends("aliti"))
				{
					r("al");
					break;
				}
				if (ends("iviti"))
				{
					r("ive");
					break;
				}
				if (ends("biliti"))
				{
					r("ble");
					break;
				}
				break;
			case 'g' :
				if (ends("logi"))
				{
					r("log");
					break;
				}
		}
	}
	/* step4() deals with -ic-, -full, -ness etc. similar strategy to step3. */
	private final void step4()
	{
		switch (b[k])
		{
			case 'e' :
				if (ends("icate"))
				{
					r("ic");
					break;
				}
				if (ends("ative"))
				{
					r("");
					break;
				}
				if (ends("alize"))
				{
					r("al");
					break;
				}
				break;
			case 'i' :
				if (ends("iciti"))
				{
					r("ic");
					break;
				}
				break;
			case 'l' :
				if (ends("ical"))
				{
					r("ic");
					break;
				}
				if (ends("ful"))
				{
					r("");
					break;
				}
				break;
			case 's' :
				if (ends("ness"))
				{
					r("");
					break;
				}
				break;
		}
	}
	/* step5() takes off -ant, -ence etc., in context <c>vcvc<v>. */
	private final void step5()
	{
		if (k == 0)
			return; /* for Bug 1 */
		switch (b[k - 1])
		{
			case 'a' :
				if (ends("al"))
					break;
				return;
			case 'c' :
				if (ends("ance"))
					break;
				if (ends("ence"))
					break;
				return;
			case 'e' :
				if (ends("er"))
					break;
				return;
			case 'i' :
				if (ends("ic"))
					break;
				return;
			case 'l' :
				if (ends("able"))
					break;
				if (ends("ible"))
					break;
				return;
			case 'n' :
				if (ends("ant"))
					break;
				if (ends("ement"))
					break;
				if (ends("ment"))
					break;
				/* element etc. not stripped before the m */
				if (ends("ent"))
					break;
				return;
			case 'o' :
				if (ends("ion") && j >= 0 && (b[j] == 's' || b[j] == 't'))
					break;
				/* j >= 0 fixes Bug 2 */
				if (ends("ou"))
					break;
				return;
				/* takes care of -ous */
			case 's' :
				if (ends("ism"))
					break;
				return;
			case 't' :
				if (ends("ate"))
					break;
				if (ends("iti"))
					break;
				return;
			case 'u' :
				if (ends("ous"))
					break;
				return;
			case 'v' :
				if (ends("ive"))
					break;
				return;
			case 'z' :
				if (ends("ize"))
					break;
				return;
			default :
				return;
		}
		if (m() > 1)
			k = j;
	}
	/* step6() removes a final -e if m() > 1. */
	private final void step6()
	{
		j = k;
		if (b[k] == 'e')
		{
			int a = m();
			if (a > 1 || a == 1 && !cvc(k - 1))
				k--;
		}
		if (b[k] == 'l' && doublec(k) && m() > 1)
			k--;
	}
	/**
	 * Stem the word placed into the Stemmer buffer through calls to add().
	 * Returns true if the stemming process resulted in a word different from
	 * the input. You can retrieve the result with
	 * getResultLength()/getResultBuffer() or toString().
	 */
	private void stem()
	{
		k = i - 1;
		if (k > 1)
		{
			step1();
			step2();
			step3();
			step4();
			step5();
			step6();
		}
		i_end = k + 1;
		i = 0;
	}
	/**
	 * Test program for demonstrating the Stemmer. It reads text from a a list
	 * of files, stems each word, and writes the result to standard output. Note
	 * that the word stemmed is expected to be in lower case: forcing lower case
	 * must be done outside the Stemmer class. Usage: Stemmer file-name
	 * file-name ...
	 */
	private void test(String[] args)
	{
		char[] w = new char[501];
		Porter s = new Porter();
		for (int i = 0; i < args.length; i++)
			try
			{
				FileInputStream in = new FileInputStream(args[i]);
				try
				{
					while (true)
					{
						int ch = in.read();
						if (Character.isLetter((char) ch))
						{
							int j = 0;
							while (true)
							{
								ch = Character.toLowerCase((char) ch);
								w[j] = (char) ch;
								if (j < 500)
									j++;
								ch = in.read();
								if (!Character.isLetter((char) ch))
								{
									/* to test add(char ch) */
									for (int c = 0; c < j; c++)
										s.add(w[c]);
									/* or, to test add(char[] w, int j) */
									/* s.add(w, j); */
									s.stem();
									{
										String u;
										/* and now, to test toString() : */
										u = s.toString();
										/*
										 * to test getResultBuffer(),
										 * getResultLength() :
										 */
										/*
										 * u = new String(s.getResultBuffer(),
										 * 0, s.getResultLength());
										 */
										System.out.print(u);
									}
									break;
								}
							}
						}
						if (ch < 0)
							break;
						System.out.print((char) ch);
					}
				}
				catch (IOException e)
				{
					System.out.println("error reading " + args[i]);
					break;
				}
			}
			catch (FileNotFoundException e)
			{
				System.out.println("file " + args[i] + " not found");
				break;
			}
	}
	public static void main(String[] args)
	{
		// System.out.println("EQUIV STEM: " + equivStems("own","owner"));
		String[] args_terp = {"-p", "terp.params"};
		TERpara params = new TERpara(args_terp);
		//Porter p = Porter.getInstance(params);
		Porter p = new Porter(params);
		System.out.println(p.stem("an"));
	}
}
